Cytoplasmic alpha-glycerol phosphate dehydrogenase (EC1.1.1.8) is an enzyme which is likely to play a particularly significant role in metabolism because it functions at a point linking glycolysis with lipid breakdown and biosynthesis. In conjunction with the flavin-linked mitochondria alpha-glycerol phosphate dehydrogenase, the cytoplasmic enzyme also functions to transfer reducing equivalents across the mitochondrial membrane. The basic aim of the proposed research is to obtain a better understanding of the functional role in cellular metabolism of alpha-glycerol phosphate dehydrogenase (alpha-GPDH) isolated from rabbit heart and aorta tissue. The first phase of the project will involve the isolation, using affinity chromatography, of the enzyme from these tissues and characterization in terms of the isozymes or multiple molecular forms present. Secondly, the enzyme will be characterized with respect to its kinetic properties, with respect to substrate binding and with respect to the effect of cellular constituents on the enzymic activity. An understanding of these properties will provide a more complete picture of the interrelationships between carbohydrate and lipid metabolism and the cellular forces operating to regulate these processes. Alterations in the activity of alpha-GPDH and their effect on lipid metabolism may be correlated with certain disease states in mammalian organisms. It is well known that excess deposition of lipids may damage the vascular wall. In light of the fact that alpha-GPDH participates in the production of a compound facilitating the deposition of fatty acids as triglycerides, this enzyme may play an especially significant role in the pathogenesis of atherosclerosis.